Sunrun & Tesla Solar Roofs & Batteries Saving The Day In California

The heatwave that’s been hitting California and other states in the West has been a beast of a problem. It’s crippling grids, which even has utilities and governments asking people to not charge their electric cars, turn down their AC, and wear dirty clothes rather than do the laundry*. What’s really needed, though, is more solar and more battery storage. Having more distributed, decentralized, clean energy and energy storage is critical to the ongoing challenge of a heating world.

As tough as it’s been this past week, it could be much worse. Thanks to dozens or hundreds of solar PV and battery companies, the California grid is much better equipped to deal with these challenges than it would have been a decade ago. A leading force in these industries is Sunrun, the largest home solar and battery storage company in the USA. Sunrun has installed more than 700,000 solar systems across the country, the bulk of which are in California, and more than 30,000 solar + battery systems. Those systems, and especially the ones with batteries, are keeping the grid on its feet in these trying times. As my daughters would say, they’re saving the day.

“The world’s largest concentration of grid-connected lithium-ion batteries helped California ride through its most acute energy emergency since widespread rolling blackouts hit the Golden State in August 2020,” S&P Global writes. “‘I would say that in general, the battery storage fleet performance has been outstanding,’ California ISO President and CEO Elliot Mainzer said Sept. 8 during an unprecedented heat wave that has driven California’s demand for electricity to new heights.”

Regarding that battery storage fleet, Sunrun reports that it dispatched 18,000 residential battery storage systems every day to help manage the pressure.

The immense amount of solar power in California provides important megawatt-hours of electricity during high-demand periods of the day, but as the sun starts to go down and those solar systems stop collecting energy and producing electricity with it, it’s the battery storage that does the extra heavy lifting and comes to the rescue. Thanks, B.

S&P Global notes that California had approximately 884 megawatts (MW) of power capacity in place from small-scale battery systems at the beginning of August. That’s located at approximately 77,000 homes and businesses, and it supplements ~4,000 MW of utility-scale battery storage capacity. It’s also a perfect example of how a lot of little actions can add up to a big effect. You can add solar and battery storage to your home and it’s a big deal for your home, but it’s a drop in the bucket for the grid as a whole. However, a lot of drops in the bucket (~77,000) is the only way you get that massive 884 MW of power capacity.

“Two years ago, just before Mainzer took the helm at CAISO, the grid operator could not even muster 200 MW of battery discharge on back-to-back days of rotating outages. This time around, with battery output hitting nearly 3,400 MW at one point during the capacity crunch, a full-blown crisis was avoided.”

In the graph above, you can see how battery storage surges from about 5pm to 10pm, and then again from about 6am to 7am, providing electricity at times of critical need and high stress. In the evening of September 5, it surged to well above 3,000 MW for a period of time.

S&P Global also references the 3,600+ residential Tesla batteries combining as a “virtual power plant” for PG&E, saying that they are “participating in California’s emergency load reduction program as a remote-controlled hive of distributed batteries.” These batteries combined for an output of 24 MW at times. The 3,600+ total comes from Tesla inviting more than 25,000 Tesla battery owners to participate in the program.

The grid is rapidly evolving, and at just the right time. One more distributed clean energy players is looking to put its own stamp on the story and bring solar plus batteries to the table in another way to help customers avoid a grid crisis. “Sunnova Energy International Inc. is pursuing a different model. In a recent filing to the California Public Utilities Commission, the company asked for approval to own and operate solar-powered, battery-backed microgrids at new master-planned residential communities of 500 to nearly 2,000 new homes as a ‘micro-utility’ to compete against PG&E and other big investor-owned utilities.” We’ll have to keep an eye on that request and hopefully report on the project coming to life in the coming years.

*Okay, I haven’t heard of this one and it might be an invention of my mind.